Apparatus for reconditioning a heavy workpiece and method

ABSTRACT

A method for the in-situ reconditioning of a heavy workpiece mounted on the floor. The method comprises assembling a jig mounted on the floor so as to be arranged around the workpiece to be reconditioned, that is also mounted on the floor, the jig supporting a gantry at the two ends of same, on which there is mounted a precision robotic arm carrying at least one machining apparatus. The method also comprises the alignment of the workpiece and the jig using a precision laser alignment tool in order to allow the jig, the gantry and the robotic arm to form a precision machining apparatus. The method also comprises the reconditioning of the workpiece using the precision machining apparatus.

This application is a continuation of U.S. patent application Ser. No.16/472,296 with a filing date of Nov. 15, 2017, which claims thepriority of the French patent application No. 1,663,355 with a filingdate of Dec. 23, 2016.

FIELD

The invention relates to the field of reconditioning heavy parts,especially those found in hydroelectric plants and wind turbines, suchas parts making up hydroelectric turbines.

CONTEXT

Hydroelectric turbines and wind turbines are composed of bulky partswith a significant weight. Many of these parts may weigh hundreds oftons and span several meters. For example, the Francis turbine, ahydraulic turbine, suitable for medium drop heights and medium andstrong powers and flows, may weigh around 450 tons and have a diameterof approximately ten meters. Moreover, the Kaplan turbine is apropeller-type hydraulic turbine, suitable for small falls, with somehaving an 11 meters diameter.

The size and weight of these parts make overhauling and maintenancedifficult. Heavy parts that need reconditioning in hydropower plantsare, for example, a Francis or Kaplan type wheel, a wicket gate, a drafttube, an alternator, runner blades, a shaft or a gate opening ring.

In the case of hydroelectric turbines, given their size and weight, itis difficult, given the state of the art, to carry out in-situ repairs,thus in the hydroelectric plant. Moreover, it is common to have to movethe part of the hydraulic turbine to an outside site, having thenecessary infrastructure to perform the reconditioning. However, thetransfer of the part of the hydraulic turbine is long, expensive andgreatly inconvenient for the following reasons.

First, hydroelectric plants, in view of the space occupied by them, areoften located far from industrialized areas where the sites to performthe reconditioning exist. Thus, it is necessary to transport the turbinepart for long periods to get to the site. This transfer is tediousconsidering the size of the part to recondition. In particular, theparts must be transported for long distances while avoiding, forexample, overpasses. This transfer may cause a temporary blockage of theroads on which the part is being transported. Transport is also veryexpensive in terms of fuel and often requires specialized equipment orspecific transport vehicles to secure the heavy part during transport.In addition, the transport of the part by the road may require obtainingspecific permits. There are also risks of accidents related totransportation. On the other hand, in countries where there is freezingrisks, it is possible to have to wait for thaw periods beforetransporting the heavy part, resulting in additional delays.

Secondly, during the period of the transport of the heavy part to thereconditioning site, including the time taken for its reconditioning, aswell as the time required to return the heavy part and reinstall it, theturbine in question is not functional. Thus, there is a loss ofelectricity production related to the period of transfer andreconditioning of the part. Given the time taken for the transfer, theselosses are often very important and are preferably avoided.

Thus, the costs and delays associated with the reconditioning of a heavypart, such as a wind turbine or hydraulic turbine, are very important.The development of a system that avoids, at least in part, these costsand delays would be preferable.

SUMMARY

The applicant has developed a precision reconditioning apparatus,portable and storable, that may be used in a hydroelectric power plant,or near the power generation system, to perform reconditioning of theheavy parts. This device allows the reconditioning of heavy parts whileavoiding costs and lost time associated with transporting the workpieceto an external site.

The reconditioning device may be assembled from several segments so thatit is easy to transport and store. A step of aligning the device isperformed during and after installation to properly adjust thedimensions and positioning of the device, before the positioning of theheavy workpiece relative to it, and after the positioning of the heavyworkpiece. The alignment is performed with a laser alignment tool toobtain the required accuracy during this step. It is also important thatthe alignment step takes into account the positioning of the heavyworkpiece with regards to the components of the reconditioning device,such as the jig.

Once the alignment is completed, it is possible to carry out the repairsof the heavy workpiece with precision, the dimensions of the heavyworkpiece and the reconditioning device being known and verified by thealignment step. The heavy workpiece may then be reinstalled. Thereconditioning apparatus may also be dismantled and stored, so that itminimizes the space taken when not in use. The device may be taken outand reused when it is next used.

A first aspect is an in-situ reconditioning process of a heavy workpiecemounted on the floor. The method is characterized in that there is theassembly of a jig mounted on the floor, to be placed in proximity of thepart to be reconditioned, also mounted on the floor, the jig carrying amount on which is mounted the precision robotic arm carrying at leastone machining unit. The method also includes the alignment of theworkpiece and the jig with the aid of a precision laser alignment toolin order to allow the jig, the frame and the robotic arm to create aprecision machining apparatus. The process also comprise machining theworkpiece using the precision machining device.

According to an example of the method, the assembly of the jig iscarried out so that the jig is arranged around the workpiece to bereconditioned, the frame includes a gantry, and the jig supporting thegantry at both ends.

According to an example of the method, it may be characterized in thatthe jig is configured so that a portion of the jig moves relative to thefloor, the reconditioning may include the displacement of this portionof the jig relative to the floor.

According to one example of the method, the method may also include thedisplacement of the portion of the jig being performed using a rollergear system mounted on precision bearing which operates through arack-and-pinion attached to the jig.

According to an example of the method, the jig may also have a centralstilt and an annular turntable centered around the central stilt, theassembly step may have the positioning of the workpiece to bereconditioned around the central stilt and the gantry supported by oneof its two ends on the central stilt and the other of its said two endson the turntable.

According to an example of the method, the annular turntable may havesections forming superimposed rings, the assembly may include thearrangement and assembly of the sections forming the two superimposedrings around the workpiece to be reconditioned. The assembly may alsoinclude the positioning of the turntable and the workpiece to bereconditioned so that the turntable and the workpiece to bereconditioned are concentric.

According to an example of the method, the method may also include,prior to assembly, the positioning of stilts on the floor using aprecision laser alignment tool and the adjustment of the stilt's heightusing a precision laser alignment tool, the stilts being positioned toreceive the workpiece to be reconditioned and the jig.

According to an example of the method, the assembly may also provide forbolting the stilts to the floor.

According to one example of the method, the method may also include theadjustment of the stilts using a precision laser alignment tool once thestilts received the workpiece to recondition and the jig in order tocompensate for the floor variations on which is placed the stilts whichreceived the workpiece to be reconditioned and the jig.

According to an example of the method, the assembly may also include theuse of wedges between the stilts and the jig and between the stilts andthe workpiece to be reconditioned in order to minimize the wear of thestilts during the reconditioning.

According to another example of the method, the robotic precision armcarries a welding tool adapted to add metal to the heavy workpiece, andthe reconditioning may provide for the welding of the heavy workpiece tobe reconditioned.

A second aspect is a renewable electricity generation process, throughan electricity generation system, consisting of heavy parts used in thepower generation system. The electricity generation process includes theproduction of electricity, and the determination if a part of the powergeneration system needs reconditioning. The process also includes thereconditioning, according to the in-situ reconditioning processdescribed herein, and the resumption of power generation.

The power generating process may be a hydroelectric generating system,the electricity generating system may be a hydroelectric generatingstation, and the power generating system component may be a part of ahydro turbine. The process may also be a kinetic energy conversionprocess of the wind into electrical energy (wind energy), the powergeneration system being a wind turbine, and the component of theelectricity generation system a component of the wind turbine. The partmay be either a Francis type moving wheel, a Kaplan type moving wheel, awicket gate, a draft tube, an alternator, a runner blade, a shaft, acrown, an upper floor, a lower floor or a c gate opening ring. The partmay also be one or more blades, a wind turbine orientation system, thegearbox, the nacelle or the rotor control hub shaft.

A third aspect is a precision reconditioning apparatus for a heavyworkpiece mounted on the floor. The apparatus includes a jig comprisinga central stilt and an annular turntable centered around the centralstilt. The apparatus includes a gantry with two ends configured to besupported at one of its two ends on the central stilt and the other ofits two ends on the turntable. The device includes a robotic armmountable on the gantry, the robotic arm configured to receive amachining apparatus for realigning the heavy workpiece.

According to an example of the apparatus, the robotic arm may include atleast one machining apparatus.

According to an example of the apparatus, the at least one machiningapparatus may include a welding tool adapted to add metal to theworkpiece.

According to an example of the apparatus, the turntable may include afixed part and a moving part, the fixed part being connected to themoving part by a precision bearing system.

In one example of the apparatus, the precision bearing system may be aprecision roller system of bearing-supported roller pinions whichengages with a rack attached to the jig.

According to one example of the apparatus, the apparatus may include atleast three height adjustable stilts for receiving the turntable toallow the leveling of said turntable.

According to an example of the apparatus, each of the height adjustablestilts for receiving the turntable may include a wedge configured to beplaced between the turntable and each of the stilts to receive theturntable.

According to an example of the apparatus, the apparatus may include atleast three height adjustable stilts to receive the heavy workpiece andto allow the leveling of the heavy workpiece.

According to an example of the apparatus, each of the height adjustablestilts for receiving the heavy workpiece may include a wedge configuredto be placed between the heavy workpiece and each of the stilts toreceive the heavy workpiece.

According to an example of the apparatus, the turntable may be composedof a segments assembly in the form of an arc.

A fourth aspect is a robotic jig for machining or precisionreconditioning of a heavy workpiece mounted to the floor. The jigincludes a ring-shaped turntable consisting of an assembly of arc shapedsegments to constitute a fixed part and a movable part, the fixed partbeing connected to the movable part by a precision bearing system, theturntable being able to surround the heavy workpiece mounted on thefloor. The jig includes at least three height adjustable stilts to allowfor the leveling of said turntable. The jig includes a precisiondisplacement system including the precision bearing system for movingthe movable portion relative to the fixed part of the turntable.

According to an example of the jig, the jig may include a mount for arobotic tool on the moving part allowing the tool an all-around accessto the heavy workpiece mounted to the floor.

According to an example of the jig, the frame may include a gantryhaving two ends, the gantry supported at a first of its two ends on theturntable.

According to an example of the jig, the jig may include a central stilt.

According to an example of the jig, the gantry may be supported at asecond of its two ends on the central stilt.

According to an example of the jig, the precision bearing system may bea precision system of bearing-supported roller pinions which engageswith a rack attached to the jig.

According to an example of the jig, each of the stilts may include awedge configured to be placed between the turntable and each of thestilts.

DESCRIPTION OF FIGURES

The invention will be better understood with the aid of the descriptionwhich follows, with reference to the following appended figures:

FIG. 1A is an isometric view from above illustrating an exemplaryprecision reconditioning apparatus with an exemplary heavy workpiece.

FIG. 1B is an isometric view from below illustrating an exemplaryprecision reconditioning apparatus with an exemplary heavy workpiece.

FIG. 2 is a top view illustrating an exemplary jig and exemplary stilts,with magnified views of different components making up the jig.

FIG. 3 is a top view of an exemplary gantry on which is mounted anexemplary precision robotic arm carrying an exemplary reconditioningapparatus.

FIG. 4 is a front view of an exemplary stilt with exemplary wedge.

FIG. 5 is a front view of an exemplary central stilt.

FIG. 6 is a flow chart of an exemplary method of reconditioning a heavyworkpiece using a reconditioning apparatus.

FIG. 7 is an isometric view of an exemplary jig and exemplary stilts andan alignment system including a precision laser alignment tool.

DETAILED DESCRIPTION

In order to avoid the losses associated with transporting the heavyworkpiece to an external site for reconditioning, it is advantageous todevelop an in-situ reconditioning machine, to be used near thehydroelectric plant, with a degree of accuracy that is at leastcomparable to that found at these external reconditioning sites.However, given the size (ex: more than ten meters in diameter) andweight (ex: hundreds of tons) of the workpiece to be reconditioned, suchdevice must be able to support such a heavy part, while offering a wayto recondition this workpiece to a degree of precision sufficient toavoid that the part loses its functionality when it is reinstalledfollowing its reconditioning.

However, in order to carry out the in-situ reconditioning of a heavyworkpiece, such as those constituting a hydraulic or wind turbine, thereconditioning device is preferably portable and may be stored when notin use, given the necessary size of the apparatus to accommodate suchheavy workpieces.

FIGS. 1A and 1B illustrate an exemplary precision reconditioningapparatus 100 and a heavy workpiece 140 to be reconditioned. Thisapparatus 100 has a jig 150, and a gantry 110 on which is mounted anexemplary precision robotic arm 115 carrying an exemplary reconditioningapparatus 116. The jig 150 and the heavy workpiece 100 may be supportedon stilts 154, such as those illustrated in FIG. 2.

In order to obtain the degree of precision necessary during thereconditioning, the aligning of the reconditioning apparatus 100,including its jig 150, is necessary. This will be demonstrated in FIG.6, illustrating an exemplary process for reconditioning a heavyworkpiece using a precision reconditioning apparatus, such as theprecision reconditioning apparatus 100. The reconditioning process isperformed on a hard surface, such as a floor, as this surface mustsupport the weight of the reconditioning device and of the heavyworkpiece and not cause, for example, excessive soil compaction.Furthermore, any deformation of the ground or the floor must be takeninto account during the aligning to obtain the necessary precisionduring reconditioning.

The first step 601 is characterized by the positioning of the stilts onthe floor. In some examples, some stilts will receive the jig and otherstilts will receive the heavy workpiece. Thus, the stilts must bedistributed on the floor in a specific configuration to receive the jigand the heavy workpiece, but also be placed relative to each other inorder to properly distribute the weight of the heavy workpiece and thejig. Thus, the location of the stilts is important for these ends.

The positioning of the stilts may be performed using a precisionalignment tool, for example, a tracking laser with a probe, as known inthe art. In the example of the tracking laser with a probe, the probe isused to measure distances between itself and the laser, the useradjusting the position of the stilts or the alignment as a function ofthe readings obtained from the tracking laser. With the laser alignmenttool, it is possible to precisely position the stilts at fixed distancesfrom each other. In some examples, there are eight stilts to receive theheavy workpiece and eight stilts to receive the jig. It is appreciatedthat the number of stilts respectively receiving the heavy workpiece andthe jig may vary depending, for example, on the weight, dimensions orsize of the workpiece.

There may also be the positioning of sub-stilts, being in some examplessmaller than the other stilts, to provide additional support for theheavy workpiece. In some examples, the sub-stilts may be placed around acentral stilt, the location of the sub-stilts may be calculated usingthe same alignment techniques described herein.

The location of the stilts may be done using software, calculating thelocation of each stilt. The laser alignment tool may identify thelocations on the floor where each stilt should be placed.

According to the readings obtained from a measurement tool in step 602,the height of the stilts is also adjusted in order to receive the jigand the workpiece to be reconditioned. In some cases, each peg may havean adjustable screw for adjusting the height of each peg. In some cases,the measurement tool may be the laser alignment tool, where the lasersensor may be placed on the top of each stilt in order to calculate itsheight. It is thus possible to make a first height adjustment and, ifnecessary, also of the position, of each stilt as a function of thereadings received from the tracking laser at step 603. In some examples,the height of each stilt may be calculated with a tape measure, where analignment step at higher accuracy will be carried out at a later stage,thus when the jig and the heavy component are placed on the stilts.

It is also possible, in some examples, to install a central stilt thatwill receive, for example, one side of the gantry. The central stilt maybe installed and adjusted using the same alignment steps as those usedto install the other stilts.

In some examples, the stilts are also bolted to the floor to minimizeany movement thereof during the steps of installation of thereconditioning device and the reconditioning itself. It is appreciatedthat any other technique for anchoring the stilts to the floor may beused.

Once the stilts are properly placed and adjusted, the jig is assembledat step 604. The jig may be a turntable (as illustrated, for example, inFIG. 1A) of annular form composed of several segments. In some examples,the annular shape of the jig is adapted to enclose the heavy workpieceto be reconditioned (eg. when the heavy workpiece has a disk shape, suchas a Kaplan wheel or a Francis wheel). However, the shape of the jig mayalso vary depending on the shape and characteristics of the heavyworkpiece to be reconditioned.

In the case where the jig is composed of a plurality of segments formingan annular turntable, the segments may be joined together to form thering before being placed on the stilts. In some examples, the turntableis constituted by quarters forming the ring. However, the number ofsegments may vary. The jig may also be formed by two superimposedsegmented rings, the two segmented rings forming the turntable. In theseexamples, the segments of the first ring may be installed first, andthen, secondly, the segments forming the second ring are installed atop.In other examples, the two rings may be assembled together, andsubsequently placed together on the stilts.

The heavy workpiece is subsequently placed on the stilts which areplaced to receive the heavy workpiece at step 605. Considering the sizeand the weight of the heavy workpiece, it may also be transported andplaced on the stilts using a gantry crane.

Then, the jig is positioned on the stilts that are placed to receivethis in step 606. The jig may be installed on the stilts with a gantrycrane. The jig may be placed around the heavy workpiece.

In some examples, it is also possible to place wedges between the headsof the stilts and the jig, and the heads of the stilts and the heavyworkpiece in order to minimize wear, such as wear of the heavy workpiececaused during its centering.

Subsequently, the gantry is placed and installed on the reconditioningapparatus at step 607. The gantry may also be transported by a gantrycrane. In some examples, the gantry is joined to the central stilt onone side, and on the other side to the turntable, and, for example,bolted at both ends (eg. the upper surface of the ring of the top of theturntable when this consists of two rings). It is appreciated that othermeans for anchoring the ends of the gantry to the central stilt and/orto the turntable may be used. Furthermore, in other examples, thedimensions of the gantry may change and the gantry may be anchored indifferent places, such as a gantry that is the diameter of the jig (ex:when the jig is annular), the two ends of the gantry anchored to the jigat two diametrically opposed locations on it.

The gantry is also configured to accommodate the robotic arm attached tothe reconditioning tool. The configuration between the reconditioningtool and the robotic arm, placed on the gantry, may allow thereconditioning tool to have access to all of at least one surface of theheavy workpiece in order to carry out the necessary overhaul. Thereconditioning tool may be, for example, a machining tool, adapted toremove material from the heavy workpiece. The reconditioning tool mayalso be a welding tool for adding metal to the heavy workpiece. It isappreciated that the reconditioning tool may be any other device, suchas a stripping tool, to perform the reconditioning of the heavyworkpiece.

Once the gantry, the jig and the heavy workpiece are installed, it ispreferable to make a second alignment at step 608. This alignment stepis often necessary because the weight of the heavy workpiece (and thejig) on the floor frequently causes deformation of the floor. Thisdeformation of the floor also causes a change in the position of the jigand gantry with respect to the heavy workpiece. Thus, it is necessary toperform the leveling and the jig alignment to readjust the position ofthe reconditioning apparatus to compensate for the deformation of thefloor. Alignment and leveling may be done using the laser alignmenttool. In the case of the tracking laser and its probe, the probe may beused in taking measurements by being placed at different places on thejig, and the stilts may be readjusted according to the measurementstaken, according to the necessary calculations to perform, by forexample, a leveling of the jig. Other measures may be taken with thelaser alignment tool to ensure that the adjustments made are sufficientto level the reconditioning device (including the jig). This secondalignment and leveling exercise is necessary to obtain the desired levelof precision during reconditioning. The angles and positions of theapparatus and the jig must be known in order to be able to effectivelycontrol the reconditioning tool digitally, allowing precisereconditioning.

Further, in examples where the heavy workpiece has a disc shape and theturntable has an annular shape, the position of the heavy workpiece andthe position of the turntable surrounding the ring are adjusted so thatthey are concentric in step 609. This positioning may also be performedusing the laser alignment tool. The tracking laser probe is placed atdifferent locations on the heavy workpiece and at different locations onthe jig. Depending on the measurements received from the probe and thetracking laser, it is possible to calculate the center of the heavyworkpiece and the jig, and what displacements are necessary so that thetwo centers come together, using calculations as known in the art. Thenecessary adjustments may also be made by changing the height orlocation of the stilts. Concentricity is preferable to facilitatedigitally performed reconditioning.

Subsequently, there may be an additional step of alignment to verifywhether the jig, the gantry and the reconditioning tool are aligned,performing these verifications along the x, y and/or z axes at step 610.This verification may also be performed using the laser alignment tool.For example, it is possible to check the displacement of thereconditioning tool along the three axes and correct any unwanteddisplacement difference by using, for example, wedges, or by adjustingthe height stilts. For example, it is possible to check the position anddimensions of the gantry with regards to the heavy workpiece and thejig, and make any adjustment or correction of any error along the axesusing wedges.

Once the alignment is completed, it is now possible to recondition themachine in step 611. The reconditioning may be aimed at repairingcertain workpieces or make certain shape transformations to the heavyworkpiece in order to optimize its functionality. The reconditioning maybe, for example, a cutting or machining of the heavy workpiece, orwelding thereof. Thus, the robotic arm may support, for example, amachining and welding tool. The reconditioning process may be undertakenentirely numerically, as the alignment has made it possible to obtainprecise dimensions of the jig, the heavy workpiece and the placement ofthe heavy workpiece with respect to the jig and the gantry. Moreover,the gantry, fixed to the robotic arm, may allow the reconditioning toolto access the entirety of a surface from the heavy workpiece, in orderto recondition the surface anywhere without manual intervention.

Finally, once the heavy workpiece is reconditioned, it may bereinstalled. For example, in the case of a hydroelectric power plant,the heavy workpiece may be reinstalled, to allow the hydro turbine tostart generating electricity again. However, as the time lost intransporting the heavy workpiece to the external site is avoided, thetotal period of non-operation of the turbine during its reconditioningis reduced, thus also reducing the production losses associatedtherewith. Moreover, the result of the reconditioning of the heavyworkpiece may be comparable to the result if this part would have beenreconditioned at an external site.

Following the reconditioning of the workpiece, the reconditioning devicemay be dismantled and stored until the next time a reconditioning of aheavy workpiece would be necessary.

Electricity Production:

The method of reconditioning a heavy workpiece may be used in thecontext of the production of electricity, such as the electricityproduced by a hydroelectric plant or wind turbines.

For example, the power generation system may produce electricity untilit is determined that the reconditioning of one of the heavy parts isnecessary. For example, reconditioning may be necessary to repair abroken part, overhauling it for better performance, or optimizing theshape of the part to increase its efficiency. As a result, the heavypart in question may be removed from the power generation system.Following the dismantling, it is possible to recondition the heavy partby following the method described herein.

Following the reconditioning of the heavy workpiece, it may bereinstalled, and electricity production may start again. As mentioned,the reconditioning step is accelerated using the present reconditioningmethod, as it is no longer necessary to waste time in transporting theheavy workpiece to an external site for reconditioning.

In some examples, the power generation process is that of the productionof hydroelectricity. This production may be carried out in ahydroelectric power plant where the heavy parts to be reconditioned are,for example, those of a hydraulic turbine used for the production ofhydroelectricity. Examples of parts to be reconditioned are a Francistype moving wheel, a Kaplan type moving wheel, a wicket gate, a drafttube, an alternator, runner blades, a shaft or a gate opening ring. Itis appreciated that this list is not limiting, any other part used in ahydroelectric plant may be subject to reconditioning in accordance withthe present teachings.

The Reconditioning Apparatus 100:

Referring to FIGS. 1A, 1B, and 2, the reconditioning apparatus 100 willnow be described in greater detail.

The Jig 150:

The jig 150 is a support that surrounds at least a portion of the heavyworkpiece 140 and serves as a support for the gantry 110. The jig 150may be annular in shape, thus encircling the heavy workpiece 140.However, in other examples, the jig 150 may also have another shape,such as that of a cylinder, depending on the shape of the parts to bereconditioned. In some examples, the jig 150 is formed of severalsegments to be transportable and easily dismantled. The jig 150 mayeasily be stowed when not in use, which is useful if the reconditioningapparatus 100 is kept on site, and taken out when reconditioning of apart is required.

In some examples, the jig 150 may have a turntable consisting of a fixedportion 153 and a movable portion 152. Each portion (fixed 153 andmovable 152) may be formed from a plurality of segments. As shown inFIG. 2, in one example, the fixed portion 153 and the movable portion152 are respectively formed by four segments (e.g. arc-shaped) ofsubstantially equal dimensions. However, the number of segments of thefixed portion 153 and the movable portion 152 may be other than four(e.g. 2, 3, 6, etc.). The segmentation of the jig 150 parts facilitatesthe transport and storage of the jig 150. However, in other examples,the jig 150 may be composed of a single piece and not segments, or thatat least one of the fixed 153 and rotating portions 152 is composed ofone piece.

The segments of the fixed part 153 and movable part 152 may berespectively attached to each other using fixing means 182, 183, 171,172 and 173. Examples of the fixing means is a pin 182, coupling guides173 and 183, bolt 172 and a guide pin 171, etc. The guide pin 171 andthe coupling guides 173 and 183 may also facilitate the alignment of thesegments of the fixed portion 153 and the segments of the movableportion 152. The fastening means preferably allow the precise alignmentof the segments but also offer a reliable fastening that will endure thereconditioning of the workpiece, minimizing movements during thereconditioning process.

The jig may also be provided with core rods 156, protrusions which arefixed in the jig 150 (e.g. the fixed part 153 of the jig) and which maybe adjusted to come into contact with the heavy workpiece 110 when theheavy workpiece is placed in the center of the jig 150. The central rods156 provide additional stability to the heavy workpiece 140, therebyconnecting the jig 150 and the heavy workpiece 140.

The jig 150 may also have a moving mechanism for moving at least aportion thereof relative to the floor to, for example, allowmobilization of the gantry 110 joined to the jig 150 to manipulate theposition of the machining tool 116. When the jig 150 has a turntable,the movement mechanism may change the position of the movable portion152 on which the gantry 110 is mounted.

Thus, in some examples, the jig 150, or at least a portion thereof, asthe upper ring of the turntable, is configured to move relative to thefloor. However, since the reconditioning must be done with precision,the movement of the gantry 110 must also be done accurately, engaged bythe displacement of the jig 150, when at least one end of the gantry isjoined to the jig 150. Thus, the turntable or the jig 150 on which isjoined at least one end of the gantry 110 may be moved using a system ofgears mounted on a very high efficiency precision bearing. For example,such a system may be a roller pinion system mounted on precision bearingwhich engage with a rack attached to said jig, such as the “RollerPinion System” of Nexen™. It is appreciated that other mechanisms formoving the precision turntable may be used. As shown in FIG. 2, theremay be two racks 181, placed on each edge of the surface of the movingpart 152 which faces the fixed part 153. The rack 181 may also be anarc, in order to match the shape of the jig 150 if it has a ring shape.In other examples, when the jig has a form other than annular (ex:straight form), the rack may also be straight. The follower rollers 162may be mounted either on one or both sides of the jig 150 to engage withone or two racks 181. The follower roller 162 may be mounted on bearingsand may serve as a connection between the fixed part 153 to the movingpart 152. There may be several follower rollers 162. In the exampleswhere the rack 181 is of annular shape, the follower roller 162 may beplaced on a surface of the jig 150 perpendicular to the surface of thejig 150 on which the rack 181 is mounted. The follower roller 162 mayalso be mounted on a bracket 163, the bracket 163 being, for example,fixed to the fixed part 153 of the jig 150 with the aid of an anchoringmeans (e.g. a screw, a bolt). The follower roller 162 may also have asupport element 161.

In other examples, the jig may be fixed relative to the ground. In theseexamples, the movement of the robotic arm and the gantry may be doneindependently of the jig, the jig having no mechanism to move.

The Stilts 154:

The reconditioning apparatus 100 may have stilts 154 for receiving thejig 150 and/or other stilts 154 for receiving the heavy workpiece 140.In some examples, the stilts 154 preferably have a strength anddurability to be able to withstand the weight of a heavy workpiece 140that weighs hundreds of tons.

The stilts 154 are parts intended to serve as an abutment and/orsupport. The stilts are therefore supports (for example, either toreceive the turntable of the jig 150 and/or the heavy workpiece 140)which offer an height adjustment in order to be able to level, forexample, the jig 154 (ex: its turntable) with respect to the heavyworkpiece 140.

Referring to FIG. 4, an example of a stilt is the stilt 154 which has abody 154C, a height adjustment mechanism such as an adjustable stand154B, a head 154A and a base 154D.

The adjustable stand 154B, as it is known in the art, is an adjustableportion which allows to adjust the height of the stilt 154 toaccommodate either the heavy workpiece 140 or the jig 150. Theadjustable stand 154B may have a counter nut and a threaded rod,connected to the counter nut, to adjust the height of the stilt 154. Thebody 154C may have a mechanical tube adapted to receive at least aportion of the threaded rod of the adjustable stand 1548 in function ofthe adjustments to the height of the stilts 154.

The head 154A of the stilt 154 serves as a surface on which rest theheavy workpiece 140 or the jig 150. The head 154A may also be adapted toreceive a wedge 157, the wedge 157 between the head 154A of the stilt154 and the heavy workpiece 140 or the jig 150, minimizing wear causedeither by the friction between the stilt 154 and the heavy workpiece140.

In some examples, the base 154D may also have orifices for receivinganchoring means for anchoring the stilt 154 to a floor. The anchoringmeans may be, for example, bolts, screws, rivets. The anchoring meansprovide additional stability to the reconditioning apparatus 100. Thisprevents the unwanted movement of the stilts 154 during reconditioningor after the installation and alignment of the reconditioning apparatus.

In some examples, the body of the stilt 154 may be made of steel.

Central Stilt 151:

Reference is now made to FIG. 5, illustrating an exemplary central stilt151. The central stilt 151 is adapted to be placed in center of the jig150. The central stilt 151 is adapted to receive one end of the gantry110.

A turntable 158 may be mounted to an upper surface of the central stilt151. The turntable 158 is adapted to receive one end of the gantry 110,allowing the gantry 110 to follow the angle of rotation of the end ofthe gantry mounted to the jig 150 (in examples where the gantry 110 ismounted to the jig 150). The turntable 158 may be composed of two ringswith a bearing. In some examples, the rotating mechanism of theturntable 158 is precision and gap free.

The central stilt 151 also has a body 151A. The body 151A of the centralstilt 151 may be made of steel.

The center stilt 151 may also have a base 151C to give support to thecentral stilt 151 on the floor and for stabilizing the central stilt 151on the floor. The base 151C may be in the form of a ring or disk. Thebase 151C may also have another shape, for example that of aparallelogram (e.g. square, rectangle).

The base 151C may also have anchor holes 151C in order to anchor thecentral stilt 151 to the floor using anchoring means. Means of anchoringthrough the anchor holes 151C and entering the floor may be, forexample, bolts*, rivets, screws**. The anchoring holes 151C and theanchoring means provide additional stability to the central stilt 151and to the reconditioning apparatus. This additional stability of thecentral stilt 151 is particularly desirable in such cases where itreceives the gantry 110, in order to minimize sudden and undesirablemovements during reconditioning, these movements potentially beingsources of error.

In some examples, the central stilt may also have an adjustmentmechanism (not shown). This adjustment mechanism may make it possible tomodify the height of the central stilt. As the upper surface of thecentral stilt, receives, in some cases, an end of the gantry, theadjustment of the height of the central stilt may be desirable toaccommodate, for example, gantries, robotic arms or reconditioning toolsof varying sizes. Furthermore, the adjustment of the central stilt mayalso be desirable to accommodate heavy parts of different sizes, or theheight of the jig 150.

The central stilt 150 may also be surrounded by sub-stilts 155. Thesub-stilts may be adapted to receive a portion of the heavy workpiece140 and provide additional support thereto, and may increase thestability of the heavy workpiece 140. The positioning of the sub-stilts155 with regards to the central stilt 151 may be obtained, for example,from the readings given by the laser alignment tool.

The Gantry 110:

The reconditioning apparatus has a frame for receiving a robotic arm. Insome examples, this frame may include a gantry.

Reference is now made to FIG. 3 illustrating a gantry 110 on which ismounted a precision robotic arm 115 carrying a reconditioning tool 116.In some examples, the gantry 110 is supported at one of its ends (e.g.117) to a central stilt 151, and at its other end (e.g. end 112) to asurface 113 attached to the jig 150 (or, e.g., its turntable components152 and 153).

The gantry 110 may be attached to an attachment surface 114 connected tothe central stilt 151.

In other examples, the frame may be attached at both ends to the jig,for example to its turntable.

The gantry may also have a bridge 111 connecting its two ends. Therobotic arm 115 may be mounted to the bridge 111. The robotic arm 115may slide along the bridge 111 to assist in moving the reconditioningtool 116 to portions of the heavy workpiece 114, using, for example, asliding mechanism. The robotic arm 115 is one such as is known in theart.

In the examples where the jig 150 has a moving mechanism (e.g.motorised) with respect to the floor, the gantry 110 is attached to jig150 (and the central stilt 151) to allow movement of the gantry 110. Ifthe jig 150 has an annular shape, the displacement of the gantry 110 maybe that of a rotation around the central stilt 151, the gantry followingthe radius of the circle defining the jig 150. In the examples where thegantry 110 is joined at both ends to the jig 150, the displacement ofthe gantry 110 may also be a rotation, the two ends of the gantry 110moving in the annular shape of the jig 150.

The reconditioning tool 116 is attached to the robotic arm 115. Thereconditioning tool 116 may be, for example, a machining tool adapted toremove material from the heavy workpiece as is known in art. Thereconditioning tool 116 may also be a welding tool for adding metal tothe heavy workpiece as is known in the art. It is appreciated that thereconditioning tool 116 may be any other apparatus as is known in theart for reconditioning the heavy workpiece.

The movement of the gantry 110, the robotic arm 115 and the gantry 110may be performed digitally via a computer system. The computer systemmay send commands to control the position of the elements of thereconditioning apparatus 100 and perform the necessary reconditioning.For example, when the jig 150 has a turntable, it is possible to controlthe turntable with the computer system (e.g. the computer system and/orthe rolling system constituting a displacement system), the controlscommanding a precise displacement of the moving part 153 of theturntable. The robotic arm 115 and the reconditioning tool 116 are alsocontrollable electronically, in order to be able to recondition theworkpiece according to certain parameters provided, for example, by thecomputer system.

The Alignment System 700:

Reference is now made to FIG. 7 illustrating an alignment system 700 toperform the alignment of the reconditioning apparatus 100 in, forexample, a reconditioning method of a heavy workpiece as describedherein. The alignment of the reconditioning apparatus 100 and the heavyworkpiece 140 may be performed using a laser alignment tool 701. Thelaser alignment tool 701 may be a tracking laser, and a probe 702communicating with the tracking laser, as is known in the art. Forexample, the tracking laser with the probe may be the Leica AbsoluteTracker AT402™.

The laser alignment tool 701 may share readings of the dimensions of thereconditioning apparatus 100, such as parts of its jig 150, with theuser. Based on these readings, the user may adjust the positioning andheight of the components of the reconditioning apparatus 100, forexample, by adjusting the height of some stilts 154, or by centering thejig 150 with regards to the heavy workpiece 140.

Thus, when the laser alignment tool 701 includes a tracking laser and aprobe 702, it is possible to place the probe 702 at different locationson a surface of the reconditioning apparatus 100 (e.g. the jig 150) andobtain readings. Once a reading is obtained, it is possible to move theprobe 702 to another location (e.g. displacement 705), in order toobtain new measurements. In a first position, the probe and the trackinglaser may make a first reading 710A, and, following a displacement 705of the probe 702, they may make a second reading 710B at the secondlocation. The repositioning of the probe 702, the communication with thetracking laser, and obtaining readings, may be done as many times asnecessary to obtain sufficient information on the dimensions andposition of the various components of the reconditioning apparatus 100and the heavy workpiece 140 in order to perform their alignment,necessary to achieve the desired level of precision to recondition theheavy workpiece. For example, the alignment of the reconditioningapparatus and of the heavy workpiece may be done as the readings areshared by the laser alignment tool 701, or after obtaining a series ofreadings.

This description has been presented for illustrative purposes of theinvention. This description of the invention is not supposed to beexhaustive, nor limiting for the possible variants thereof. Severalmodifications and variations will be obvious or apparent for a personwho is skilled in the art.

1. A method for the in-situ reconditioning of a heavy workpiece mountedon a floor, the method characterized in that it comprises: assembling ajig mounted on said floor to be placed in the vicinity of said workpieceto recondition, also mounted on said floor, said jig supporting a frameon which is mounted a precision robotic arm carrying at least onemachining unit; aligning said workpiece and said jig with a laserprecision alignment tool to allow said jig, said mount and said roboticarm to form a precision machining apparatus; and machining saidworkpiece using said precision machining apparatus.
 2. The method ofclaim 1, characterized in that said assembly of said jig is performedsuch that said jig is arranged around said workpiece to bereconditioned, said frame comprising a gantry, and said jig supportingsaid gantry at both ends.
 3. The method of claim 2, characterized inthat said jig is configured such that a portion of said jig movesrelative to said floor, said reconditioning comprising moving saidportion of said jig relative to said floor.
 4. The method of claim 3,characterized in that said moving of said portion of said jig isperformed by means of a precision system of bearing-supported rollerpinions which engages with a rack joined to said jig.
 5. The method ofclaim 3 or 4, characterized in that said jig comprises a central stiltand an annular turntable centered around said center stilt, saidassembling step comprising placing said workpiece around said centralstilt, and said gantry supported at one of said two ends on said centralstilt and at the other of its said two ends on said turntable.
 6. Themethod of claim 5, characterized in that said annular turntablecomprises segments forming two superposed rings, said assemblingcomprising placing and assembling said segments forming said twosuperposed rings around said workpiece.
 7. The method according to oneof claim 5 or 6, characterized in that said assembling comprisespositioning of said turntable and said workpiece such that saidturntable and said workpiece are concentric.
 8. The method as claimed inany one of the preceding claims, characterized in that said methodcomprises, prior to said assembling, positioning stilts on the floorusing a precision laser alignment tool and adjusting height of saidstilts using a precision laser alignment tool, said stilts positioned toreceive said workpiece and said jig.
 9. The method of claim 8,characterized in that said assembling comprises bolting said stilts tothe floor.
 10. The method according to claim 8 or 9, characterized inthat said method comprises adjusting said stilts with a precision laseralignment tool once said stilts have received said workpiece and saidjig in order to compensate for deformation of floor on which are placedsaid stilts which received said workpiece and said jig.
 11. The methodaccording to any one of claims 8 to 10, characterized in that saidassembling comprises the use of wedges between said stilts and said jigand between said stilts and said workpiece to minimize the wear of saidstilts during reconditioning.
 12. The method as claimed in any one ofthe preceding claims, characterized in that said precision robotic armcarries a welding tool adapted to add metal to said workpiece.
 13. Amethod of producing renewable electricity through an electricitygeneration system consisting of heavy parts used in said electricitygeneration system, said electricity producing method characterized bycomprising. producing electricity; determining whether one of said partsof the electricity generation system requires reconditioning;reconditioning said one of said parts according to the in-situreconditioning method of any of claims 1 to 12; and resumption ofproducing electricity.
 14. The method according to claim 13,characterized in that it is a method of producing hydroelectricity, saidelectricity generation system is a hydroelectric power plant, and saidpart is a part of a hydraulic turbine.
 15. The method according to claim13 or 14, characterized in that said reconditioning of said one of saidparts is the reconditioning of either: a Francis type mobile wheel; aKaplan type mobile wheel; a wicket gate; a draft tube; an alternator; arunner blade; a bottom floor; an upper floor; a crown; a shaft; or agate opening ring.
 16. A precision reconditioning apparatus of a heavyworkpiece mounted on a floor, said apparatus characterized in that itcomprises: a jig comprising: a central stilt; and an annular turntablecentered around said central stilt; a gantry with two ends configured tobe supported at one of said two ends on said central stilt and the otherof its said two ends on said turntable; and a robotic arm mountable onsaid gantry, said robotic arm configured to receive a machiningapparatus for readjusting said heavy workpiece.
 17. The apparatusaccording to claim 16, characterized in that said robotic arm comprisesat least one machining apparatus.
 18. The apparatus according to claim17, characterized in that said at least one machining apparatuscomprises a welding tool adapted to add metal to said workpiece.
 19. Theapparatus according to any of the claims of claims 16 to 18,characterized in that said turntable comprises a fixed portion and amovable portion, said fixed portion being connected to said movableportion by a precision rolling system.
 20. The apparatus according toclaim 19, characterized in that said precision rolling system is aprecision system of bearing-supported roller pinions which engages witha rack joined to said jig.
 21. The apparatus of any of claims 16 to 20,characterized in that said apparatus comprises at least threeheight-adjustable stilts for receiving said turntable to enable saidturntable to be leveled.
 22. The apparatus of claim 21, characterized inthat each of said height-adjustable stilts for receiving said turntablecomprises a wedge configured to be positioned between said turntable andsaid each of said stilts for receiving said turntable.
 23. The apparatusof any one of claims 16 to 22, characterized in that said apparatuscomprises at least three height-adjustable stilts for receiving saidheavy workpiece and for enabling said heavy workpiece to be leveled. 24.The apparatus according to claim 23, characterized in that each of saidheight-adjustable stilts to receive said heavy workpiece include a wedgeconfigured to be placed between said heavy workpiece and said each ofsaid stilts to receive said heavy workpiece.
 25. The apparatus accordingto any one of claims 16 to 24, characterized in that said turntable iscomposed of an assembly of arc-shaped segments.
 26. A robotic jig usedfor the machining or precision reconditioning of a heavy workpiecemounted to the floor, the jig characterized in that it comprises: Anannular turntable composed of an assembly of arc-shaped segments toconstitute a fixed portion and a movable portion, said fixed portionbeing connected to said movable portion by a precision rolling system,said turntable being capable of surrounding said heavy workpiece mountedon the floor; at least three height-adjustable stilts to enable saidturntable to be leveled; and a precision displacement system comprisingsaid precision rolling system for moving said movable portion relativeto said fixed portion of the turntable.
 27. The jig according to claim26, characterized in that it comprises a mount for a robotic tool onsaid movable portion allowing said tool to access said heavy workpiecemounted to the floor from all sides.
 28. The jig according to claim 27,characterized in that said mount comprises a gantry having two ends,said gantry supported on a first of its said two ends on said turntable.29. The jig according to claim 28, characterized in that said jigcomprises a central stilt.
 30. The jig according to claim 29,characterized in that said gantry is supported at a second of its saidtwo ends on the central stilt.
 31. The jig according to any one ofclaims 26 to 30, characterized in that said precision rolling system isa precision system of bearing-supported roller pinions which engageswith a rack joined to said jig.
 32. The jig of any one of claims 26 to31, characterized in that each of said stilts comprises a wedgeconfigured to be placed between said turntable and said each of saidstilts.